Reactive iron carbonyl species via reduction of FeCl < inf > 3 < /inf > with NaBH < inf > 4 < /inf > in the presence of CO: conversion of 1-alkynes to benzoquinones and cyclobutenediones

Abstract

Iron carbonyl species, prepared in situ at 25°C through reduction of anhydrous FeCl3 with NaBH4 in the presence of carbon monoxide and acetic acid in THF, reacts with 1-alkynes at reflux temperature to give the corresponding benzoquinones after CuCl2·2H2O oxidation in moderate to good yields (51-80%). Also, these species upon CH3I treatment followed by reaction with 1-alkynes lead to the formation of the corresponding cyclobutenediones in moderate yields (30-37%) after CuCl2·2H2O oxidation.